Chronic prostatitis/chronic pelvic pain syndrome is a common but poorly understood condition affecting men of all ages. Infection has dominated the thinking about this disease for decades. However, a growing body of evidence provides significant challenge to the notion that infection contributes to symptoms in a significant proportion of patients. Much of this new information was developed by the Chronic Prostatitis Collaborative Research Network (CPCRN), a six year project representing the first NIH-funded collaborative study of chronic prostatitis. The long-term goal of this application is the continuation of our involvement in the Chronic Prostatitis Collaborative Research Network. In addition, we will collaborate with investigators studying interstitial cystitis under an umbrella group, the Urological Chronic Pelvic Pain Syndromes Collaborative Group. We describe the activities at our center over the past 7 years in the study of chronic prostatitis/chronic pelvic pain syndrome and describe the clinical and research infrastructure and expertise that we propose to continue to apply to the study of chronic prostatitis/chronic pelvic pain syndrome as part of this cooperative group.